Asphalts and method for producing same



Feb. 4, 1936. u. B. BRAY ET AL ASPHALTS AND METHOD FOR PRODUCIN( -S AME Original Filed Aug. 7, 1933 3 Sheets-Sheet l monk. kw ZONEQQBNZNQ Kuhn .DN 2b ZTEERUDQ PERCENT OIL 1N BLEND BY WEIGHT PERCENT 01L 17V BLEND BY m .5. 5 E53 EEHNE 0 Ewzmmww Eg s PERCENT 01L IN BLEND BY YYEIGH T PE 1? CENT 01L IN BLEND BY WEIGHT INVENTORS,

UZnc B..Bray BY Lam/Z022 BBecZcwz' h 6 2 M 1936' u. s. BI QAY El AL ASPHALTS AND METHOD FOR PRODUCING SAME Original Filed Aug. 7, 1953 3 Sheets-Sheet 2 pomrrmr .50 as TEMPERATURE IN E oNR. .DX

1 .5 K Eu 5 E3225 MELTING POINT IN F ATTORNEY.

Feb. 4, U B BRAY AL ASPHALTS AND METHOD FOR PRODUCING SAME 5 Sheets-Sheet 3 Original Filed Aug. 7, 1933 QON mmwkom k INVENTORS LZZFLG 5.13212 BY Lawton fiBeckwz, h

EBB U WM dized asphalt.

Patented Feb. 4, 1936 PATENT OFFICE ASPHALTS AND METHOD FOR PRODUCING SAME Ulric B. Bray, Palos Verdes Estates, and Lawton B. Beckwith, San Pedro, Caliih, assignors to.

Union Oil Company of California,

Los Angcles,

Calif., a corporation of California Original application August'l, 1933, Serial No.

684,094. Divided and this application December 18, 1934, Serial No. 758,072

Claims.

The present invention relates to asphalts and to methods for their production. The present invention is a division of our copending application Serial No. 684,094, filed August 7, 1933 now U. S. Patent 1,988,715.

It is well known that both steam refined and oxidized asphalt are composed of solid bitumens and oil. For the purpose of this discussion, the term bitumen will be used to designate the portion of the asphalt which is insoluble in liquid propane and the term oil or "raw oil to designate that portion of the asphalt which is soluble in liquid propane. The amount of oil present in the asphalt is related to several physical characteristics of the asphalt such as the melting point and penetration. An asphalt having a low melting point usually contains considerable portions of oil, while one having a high melting point indicates the presence of a small amount of oil. The occurrence of large proportions of oil in high melting point air blown asphalt is not generally recognized but we have definitely established that such asphalt contains a considerable amount of oil and can be removed by extraction with solvents'or by distillation with the aid of steam or under high vacuum.

We have discovered that if an air blown asphalt produced from a petroleum residue is separated as by. means of solvents, for example, propane, or by distillation, into its oil and bitumen constituents and 'the bitumen constituent is blended with a selected fraction of the oil constituent and/or with other oils, asphalts may be produced having different characteristics from the original oxi- Thus, if the oil constituent of the original asphalt is replaced in any desired proportion with more paraflinic fractions of the propane extracted oil or with other paraflinic or saturated typeoils, the blendedasphalt will exhibit a higher penetration at 77 F. for the same melting point and a relatively lower susceptibility to temperature change than the original oxidized asphalt. A blended asphalt of this type is more useful as a battery sealing compound or roofing cement than the oxidized asphalt from which'it has been produced. On the other hand, if the oil constituent of the oxidized asphalt is replaced in any'desired proportion with the more aromatic fractions of the extracted oil or with other aro-' matic type oils, the blended asphalt will have a lower penetration at 77 F. for the same melting point and a higher susceptibility to temperature change than the original oxidized asphalt. Such asphalts are suitable for saturating felt or fabrics because of their lower viscosities at the'saturating temperature. They may also be employed in the manufacture of pipe line coatings and to replace the Gilsonite ordinarily employed in the manufacture of paints and storage battery boxes. The asphalts mentioned herein and forming the subject of our invention will be referred to as composite asphalts.-

It is, therefore, an object of our invention to produce composite asphalt which is suitable for use as battery sealing compounds, roofing cements, for sealing cracks in pavement and for other uses where it is desirable that the asphalt have a higher penetration and ductility for a given melting point than an air blown asphalt of the same melting point and also a lower susceptibility to temperature change.

It is another object of our invention to produce synthesized asphalts which are suitable for saturating felts and fabrics where it is desirable that the asphalt have a higher susceptibility to temperature change. Other objects and advantages of our invention will be apparent from the following description of our invention taken from the drawings.

Figs. 1 to 8, inclusive, represent characteristics of the composite asphalt produced by our invention as compared'with oxidized asphalt.

Fig. 9 is a schematic arrangement of apparatus for carrying out one embodiment of our invention.

Briefly, the asphalts forming the subject of our invention may be produced by first oxidizing a petroleum residuum or topped crude with air or other oxidizing gases to any desired melting point, for example, 200 F. The oxidation will reduce the penetrationand ductility of the asphalt. The oxidized asphalt is then either steam distilled under high vacuum to remove approximately onethird of the asphalt as an overhead fraction as an oil, or it may be mixed with a solvent capable of dissolving the oil constituents of the asphalt and precipitate the bitumen. Solvents capable of eifecting this are liquefied normally gaseous hydrocarbon solvents as ethane, propane, butane, iso-butane or mixtures thereof. Such hydrocarbon solvents are obtained by rectification of casinghead gasoline by the so-called stabilizing method now conventional in the natural gasoline industry. They comprisethe overhead gaseous fractions of the stabilizing process. The gaseous fractions are liquefied by compression and cooling in the conventional manner and are .drawn oil into pressure chambers where they are maintained in the liquid state until they are used. A typical analysis of such a fraction is 6.72 ethane, 72.2%

' 201 from the oil remaining as still bottoms.

propane, 19.91% iso-butane and 1.17% normal butane. The necessary pressure to maintain this fraction in a liquid state is approximately lbs.

per sq. in. gauge at 75 F. In the present discussion of-this invention, this fraction or solvent will be referred toas fpropane" or liquid propane. It will be observed that other mixtures of these hydrocarbons may be employed, as, for example, we may employ a solvent having a greater proportion of ethane than that described above. For example, we may prefer to use a solvent comprising essentially 30% ethane and 70% propane.

When employing a liquefied normally gaseous hydrocarbon solvent to effect a separation of the oxidized asphalt into its oil and bitumen constituents, it is preferable to first cut the asphalt back, that is, reduce its viscosity, with a solvent which is liquid at normal temperatures and pressures. Such solvents may comprise naphtha, benzol and mineral spirits having a boiling range of 300 F. to 400 F. This will facilitate subse quent contact of the oil with the lighter solvent, i. e. propane.

The benzol solution having the consistency of a heavy road oil may then be extracted with approximately 300 to 500 volume percent'of the liquid propane under pressure sufiicient to maintain the propane liquid at atmospheric temperature. The propanephase of the extraction is then decanted and distilled to remove propane and [ben- This oil may be further extracted with more propane .to precipitate bitumen which has been carried over into the propane layer because of the presence of the benzol in the primary extraction. The bitumen phase from. the primary extraction may be further washed with a fresh charge of propane to remove any unseparated oils from the first extraction. The washed bitumen is mixed with a small quantity of additional bitumen precipitated in the re-extraction of the oil. The oil recovered in the rewashing of the bitumen is mixed with the oil of the primary extraction. If the oil separated from the asphalt contains wax this may Extraction data. from liquid sulphur dioxide treatment of raw oil separated from omibe separated by refrigeration and settling or filtration.

The oil is then separated by means of a selective solvent, such as liquid sulfur dioxide, into an oil having a low gravity viscosity constant, i. e. low temperature viscosity susceptibility and one having a high gravity viscosity constant, that is, a

high temperature viscosity susceptibility. The

oils having a low gravity viscosity constant are those resembling Eastern or paraflin base oils or saturated type oils, while oils of high gravity viscosity constants are those of the aromatic type. The gravity viscosity constant has been defined by Hill and Coates in the Journal of Ind. and Eng. Chem. in Vol. 20, page 641 of 1928. This constant represents the paraflinicity or naphthenicity of an oil. A high value represents a high degree of naphthenicity, while low values indicate relatively greater parafiinicity. Lubricating oils from natural crudes range from .903 for an extreme Gulf Coast type to .807 for an Eastern Pennsylvania type or even beyond. As solvents which will effect the separation of the oil into the two types, we have found liquid sulphur dioxide, mixtures of liquid sulphur dioxide and benzol, mixtures of acetone and benzol, chloraniline, nitrobenzene, furfurol, phenol, aniline or methyl formate useful.

Nitrobenzene or chloraniline alone, in addition to being an asphalt precipitant, also has, in some measure, the ability to split the oil in the above manner. Liquid sulphur dioxide has been found especially valuable as a solvent to separate the propane extract into oils having a low viscosity The characteristics of the oils thus extracted and the rafiinate may be viewedfrom an inspection of Table 1.

TABLE 1 dz'zed asphalt and physical and chemical tests on the mm 011 EXTRACTS AND RAFFINATE orns S0; treatment data Physical tests on v 1 1 t s ii i v' t v o perercen G it ay 0 t iscosi y Ananne cent of $01 by wt. of y universal gravity used raw oil OAPI in sees. constant f Raw oil None 100 is. 1 131. 5 .876 75. 5 First extract. 0-300 20. 3 11. 5 191 926 33. 0 Second extrac 300-600 8. 7 12. 8 916 42. 0 Third extract- 600900 5. 8 l4. 2 146 908 52. 5 Final 1 nate 65. 2 20. 7 129. 5 855 92. 6

CHEMICAL TESTS Proximate analysis-percent Ultimate analysis percent by weight by volume on ?ther Ash or 0 855535 Unsatu- Aroby dil- O H N rates matics ference 1 from 100 percent 2. 39 85. 0 l1. 5 0. 30 0. 81 26. 8 26. O 47. 2 3. 74 83. 5 10. 8 0. 36 l. 60 37. 6 44. 0 18. 4 3. 54 85. 6 10. 6 0. 38 -0. 12 34. 0 4 8. 4 17. 6 3. 15 83. 5 11. 4 0. 33 1. 62 26.0 38. 0 36. 0 l. 76 83. 6 12. 6 0. 16 1. 88 5. 6 1&0 80. 4

The extracts and final rafiinate shown in the 'tabiewere blended in various proportions with 'the bitumen separated'byv means of liquid propane from the oxidized asphalt. However, since the first and second extracts and final rafllnate shows the greatest divergence in characteristics from the original oil, only these constituents were blended with the bitumen in various proportions.

Blends were not made with the third extract on account of the small yields of this material and less marked dissimilarity from the original oil. The blends of bitumen with the extract covered the range of 45% to 54% oil, while those of raflinate covered the range of 45% to 66% oil. The various tests on these blends-are given in Figs. 1 to 8, inclusive. Figs. lute-4', inclusive,

show the variation in ductilityrpenetration, tensile strength and melting point by'the variation in-amounts of the oils in the mixture. Figs. 5, 6 and 7 show the variation in penetration, ductility and tensile strength by variation of melting point of the various blends, while Fig. 8 is a plot showing the temperature susceptibility of ductility of the various blends. It will be observed that the blends of extracts and rafllnate with bitumen are compared with a blend of the raw oil with the bitumen, the raw oil comprising the propane soluble portion of the original oxidized asphalt and from which the extracts and raflinate were produced. It may be stated that the blends of raw oil and bitumen correspond very closely in physical properties to ordinary air-blown asphalts of equal melting point produced by direct air blowing of the same residuum employed in the manufacture of the asphalt subjected to propane extraction.

It will be observed by reference to Fig. 1 that for any given percentage of oil, the blends of bitumen with sulphur dioxide soluble extracts have higher ductilities than blends with the raffinate, with the blends of raw oil 'falling in between. However, it will be noted from Fig. 3 that blending with the extract gives the lowest melting point and blending with the raflinate the highest for any given percentage of oil so that when blends of equal melting point are compared'as in Fig. 5, it will be observed that the extracts give superior ductilities only for blends having a lower melting point e. g. 210 F. than the original asphalt. For melting points above that of the original asphalt, the blends of rafflnate with bitumen are highest, while those with extracts are lowest in ductility for a given melt ing point.

Considering the susceptibility of ductility to change in temperature for asphalt of approximate equal melting points, it is seen from Fig. 8 that while blends of bitumen and sulphur dioxide extract are high in ductility at 77 F., they exhibit an exceedingly high rate of change in ductility with temperature .so that the asphalts of this variety with a relatively high ductility at 77 F. show markedly less ductility at temperatures below 60 F. On the other hand, a blend with raflinate shows the lowest rate of change in duetility with temperature, while those with raw oil are intermediate as would be expected. It will be observed in Fig. 8 that curves 0 and O' represent the change in ductility of asphalts composed of raw oil and bitumen, the asphalts. having melting points of 188 F. and 207 F., respectively. CurvesE, E and E" represent mixtures of extract and bitumen, the mixtures having melting points of 182 F., 189 F.,and 216 F.,- respectively. Curves R, R 'and R" represent mixtures of rafiinate and bitumen, the mixtures having melting points of 196 F., 213 F., and 230 F., respectively. To the best 01 our knowledge, the low rates of change of ductility with temperature for the blends composed of ramnate and bitumen represent a marked improvement over naturally occurring asphalts or those produced by the usual methods." The advantages possessed by an asphalt which shows practically no change in ductility and lack of brittleness over the temperature range from approximately 30 to 80 F. are obvious.

Thus, ror'ductility at 77 F. higher values are obtained for a given melting point by blending the sulphur dioxide extract with bitumen until a melting point corresponding roughly to that of the original asphalt is reached, e. g. melting point of 210 F. For melting points higher than this temperature, e. g. 210 F., the higher values are obtained by blending the raflinate with the bitumen. To produce asphalt which will showthe minimum of change in ductility with temperature, the best results are obtained by blending rafiinate with bitumen. By solvent extracting the original asphalt, subjecting the thus separated oil to Edeleanu treatment, rejecting the extract portions and blending the raflinate with the bitumen, no appreciable change in ductility at 77 F. for the same melting point is obtained as compared to the original asphalt but the susceptibility of the ductility to temperature change is very greatly reduced. The asphalt in -this manner will exhibit considerable ductility or lack of brittleness far below that temperature, at

which the original asphalt becomes sufliciently brittle to crack or chip quite easily.

By reference to Fig. 2, it will be observed that the penetration at 77 F. for the various blends of the different oils with the bitumen happens to be the same for the same percent of any of the oils in the blend so that the penetration at 77 F. is dependent only on the percentage of oil in the blend and not upon its treatment after propane extraction.

However, the melting point of the blend corresponding to a given percentage of oilis not independent of the nature of the oil but there is considerable variation in melting point for the same percentage of blends of extract, raw oil and raflinate. Thus, by referring to Fig. 6 and considering penetration for any given melting point, it is evident that the rafiinateblends have the highest penetration and the extract blends the lowest with the raw oil blend falling in between. This is the equivalent of saying that fora given penetration the rafiinate blends have the highest melting points and the extract blends the lowest melting points. When classified by the usualmelting point and penetration relation, the blends of raflinate and bitumen show more air blown characteristics than the still run asphalts, while the extract blends tend to slow more steam blown. characteristics. I I

While the theory involved in these phenomena is not established definitely, we believe that the reason for the peculiar behavior of the raflinate blends for a given melting point is that the state extract blends, the rafiinate being a relatively saturated and non-aromatic oil is not as good an asphalt solvent as the unsaturated and aromatic extracts. Theresult isthat the raflinate blends carry the asphalt in a dispersed or emulsified state as well as in true solution, while the extract blends are probably more homogeneous and more nearly approximate a'true solution of asphalt in oil. This apparent two-phase structure of rafllnate blends is probably influential in giving them a low susceptibility factor, while the low viscosity temperature susceptibility or low gravity viscosity constant of the raflinate oil itself is also probably a factor. In fact, the raflinate blends are thought to represent quantitatively an asphalt with exaggerated air blown characteristics.

.Thus, it appears that for a given percentageof oil blended with the propane insoluble bitumen, the peneration of the blend at 77 F. happens to be independent of whether the oil taken is the extract, raw oil or raffinate. For a given melting point, however, the nature of the oil taken has a very marked influence upon'the penetration at 77 F. because the melting point for a given percentage of oil varies markedly for raflinate, raw oil and extract. For a given melting point, the blends of bitumen with ramnate show the highest penetrations and the blends with extract the lowest with blends of raw oil and bitumen falling in between. For a given penetration at 77 F. corresponding to equal percentages of the different classes of oils, the melting points are different, the rafiinate blends exhibiting the highest point and the extract blends the lowest. The higher penetration for a given melting point or a higher melting .point for a given penetration for the rafiinate blends as compared to the blends of extract and raw oil are believed to be due to the different states of dispersion of the bitumen in the rafilnate. The physical tests of the raifinate blends represent exaggerated air blown characteristics and are thought to be due to-the existence .of two or more phases in air blown asphalt rather than one homogenous phase.

The tensile strength of asphalt is a property which is not usually determined but is, of course. of considerable importance in the selection of an asphalt for particular purposes, such as in the manufacture of sewer 'joint compounds and moulded plastics. The tensile strength of asphalt tional area at is measured by pulling apart in a suitable tensile strength testing machine and noting the force required to pull apart the ordinary ductility briquet of one square .centimeter cross-secthe narrowest point. Considering tensile strength as a function of percentage of oil in the blend, the variation in tensile strength between the blends of the different classes of oil may be viewed from an inspection cf Fig. 3. However, these results may possibly be mislead'ng because of the variation in melting point between the blends of the different classes of oil for a given percentage of oil. By inspecting Fig. 7 where the tensile strength has been plotted as a function of-the melting point, it will be observed that the extract blends are highest in tensile strength and the rafiii ate bllends are lowest in tensile strength with te raw oil blends falling in between. The lower tensile strength of the rafiinate blends is thought to be 'due to the dispersed or two-phased nature of these blends as compared to the more homogenous extract blends. 'I'he ..raflinate blends are more rubbery in character than the extract blends and they have a slightly dull luster as compared to the bright luster of the extract blends. Thus, the extract blends are higher in tensile strength than the raflinate blends with the blends of raw oil and bitumen falling in between and this difference is believed to be due to the diiference in state of dispersion of the blends.

From the above discussion of our invention, it is apparent that any desired.type of asphalt may be produced by the proper combination of raflinate or extract with bitumen. However, it will be observed that this invention is not to be limited by recomposition of the raflinate or extract with the bitumen produced from the raw oil separated from the bitumen since ramnates and extracts of other oils or fractions of crude oil having other gravities, viscosities and viscosity gravity constants than those indicated in Table 1 may be substituted for those indicated above. Furthermore, other types of oils resembling the raffinate such as saturated type blending agents may be substituted for the rafiinate. As examples of such oils, we may employ acid treated western oils,

such as lubricating oils or solvent treated western oils or lubricating oils such as those produced by treatment with liquid sulphur dioxide, mid-continentor eastern oils of paraiiin base or petrolatum.

Likewise, the extract for blending with the bitumen may be substituted by other oils resembling the extract'in composition. Such oils are the aromatic type blending agents. As examples of such oils; we may employ the liquid sulphur dioxide extracts from western oils or mid-continent or Pennsylvania lubricating oil stock or any kind of lubricating ol stock having a gravity of say lower than 15 A. P. 1. Such oils having gravity of less than 15 A. P. I. are more aromatic than those above this gravity. We may also employ coal tar or coal tar distillatcs, cracked petroleum oils or residues or the polymers resulting from the Gray process, that is, the polymers resulting from treating cracked gasoline in the vapor phase with clay. The blends of oil with the bitumen may be further air-blown to bring the blend to the desired specification as to melting point or other characteristics.

The above discussion has been made with great particularity with respect to the separation of oil from the bitumen by means of solvents. However, we do not wish to be limited to this exact procedure since the oil constituents of the oxidized asphalt may be separated by distillation under high vacuum and the oil recovered may be extracted to produce a rafiinate and an extract in accordance with the above procedure and the separated constituents then recomposed with the bitumen in any desired proportion of the distillate may be discarded or employed as cracking stock and replaced by other type of oils mentioned above. As an exampleJWe have produced a battery sealing compound by distilling approximately one-third of the oxidized asphalt and blending approximately 30 parts by weight of l the bottoms to 70 parts of an acid treated heavy Western lubricating oil and further air blowing Softening or melting point, Ball 8;

Ring method -D-36-26 Penetration D-5 -25 Ductility D-113-26T Flash point, Cleveland open cup method D-92-24 Referring to Fig. 9,: a topped crude oil, such as I 5 fuel oil having a gravity of 14 A. P. I. and a viscosity of 100 seconds Furol at 122 F. is taken.

from tank l and passed into line 2 controlled by valve 3 and pumped by pump 4 into an oxidizing still 5 set, in furnace 6 and heated by burners I. The, still,-is provided with perforated line 8 controlledby valve 9 for introduction of air into the still. The light hydrocarbons, fixed gases and excess air from the still 5 pass through mist extractor IO and are removed from the still through line H, condensed in condenser l2 and the condensate and uncondensed gases are then passed through line H into run-down tank l5. Fixed gases and excess air are vented through line It.

The oxidation' 'in still 15 of the fuel oil is carried on until a, test of the asphalt shows the desired characteristics, as for examplef a melting point of approximately 200 F., a penetration at 77 F. of approximately l5, a ductility of 2 cm. at 77 F. and of at 32 F. and a flash point of approximately 430 F.

Upon completion of the oxidation in still 5, the oxidized asphalt is withdrawn-via line H, controlled by valve-l 8 and pumped by means of pump i9 into line 20 where it is mixed with a liquid 30-hydrocarbon solvent such as benzol taken from .tank 2| and introduced into line 29 via line 22 controlled by valve 23 and pump 24. V Approximately 35% by weight of the solvent is mixed with the asphalt for the purpose of cutting the asphalt back or reducing its viscosity and to thus facilitate contacting in the subsequent admixture with liquid propane. The asphalt and benzol is passed through turbulence coil 25 for the purpose of eflecting intimate admixture of the solvent with the asphalt. The benzol solution of asphalt having the consistency of a heavy road oil is then passed into line 26 where it meets a stream of liquid propane taken from propane storage tank 21 via line 28 controlled by valve 29 and 45' pump 38. Approximately three volumes of propaneis mixed with one of the benzol-asphalt mixture. The propane may contain 30% ethane. The mixture is then passed through turbulence coil 3| for the purpose of effecting intimate admixture and then passed into the extractor or settling tank 32. In the extractor 32, a stratification of the mixture takes place into two layers, a lower layer consisting of bitumen and solvent and an upper layer ofoil, benzol and propane. A pressure of approximately 125 lbs. per sq. in. gauge is maintained in tank 32 for the purpose oi. maintaining the propane in a liquid state during extraction. Equilibrium line 33 controlled by valve 34 connects the extractor with propane storage tank 21 also maintained at the aforesaid pressure. The bitumen phase settling to the bottom oftank 32 is withdrawn via line 35 controlled by valve 36 andpassed topump 31 which forcesthe bitumen throughheating coil 38 where its temperatureisraised to efiect'vaporization of entrainedsolvent... I

The heatedmixture is then passed via line 39 controlled by valve 48 into evaporator 4|. Additional heat is suppliedin evaporator through closed steam coil 42. In evaporator 4 I, the vaporized solvent is passed through mist extractor 43 into line 44' controlledby valve 44' and thence through cooler 45 intoseparator 48. Condensed light oils and benzol are withdrawnvia line 41 75 while the uncondensed propane passes via line 48 into line 49 to the suction of compressor 58 where its pressure is raised to that of the high pressure system, i. e. approximately 125 lbs. per sq. in. gauge, liquefied in cooler and then passed into the propane storage tank 21. The bitumen is taken from the bottom of the evaporator 4| via line 52 controlled by'valve 52' and pumped intotank 54 by pump 53. The supernatant solution of oil, propane and benzol is decanted from tank 32 and then passed to suitable apparatus for the separation of propane. The oil-benzol mixture is then subjected to refining with liquid sulphur dioxide hereinafter described.

However, if the original oil contained wax, it is preferable to remove this wax prior to the refining step. In this case, the supernatant solution of oil, benzol and propane is decanted from the extractor 32 and passed into line 55 by means of pump 56fwhich forces the mixture' throughvalve 51 into chiller 58 maintained at a low pressure.

In chilling column 58, sufilcient propane vaporizes to reduce the temperature of the remaining material to a predetermined dewaxing temperature which causes the wax to precipitate from solution. The desired dewaxing temperature is obtained by controlling the pressure in column 58 by the proper operation of valve 68 on line 59 and compressor 58 which is connected to the evaporator by lines 59 and 49. The pressure to be maintained in column 58 will generally be about 0 lbs. gauge which corresponds to a temperature of approximately -40' F. As the propane solution passes through valve 51 its pressure is reduced so that a portion of the propane evaporates in the column 58 and the vapors pass out of the top through line 59 controlled by valves 88 then through line 49 to the suction of compressor 58 where the vapors are liquefied, cooled in 5| and passed to the propane storage tank 9.

The chilled oil dissolved in the propane and benzol carrying the precipitated wax is removed from the chilling column 58 through line 8| controlled by valve 62 by pump 63 which forces it into vapor-tight wax separator settler Hi In order to prevent ebullition or boiling in the wax separator during wax settling operation, pressure is imposed upon the solution of oil. This is accomplished' by maintaining pressure within the separator by pump 63. As the chilled mass in separator 84 remains in a non-ebullient state, the wax settles out and is collected by vanes 65 operated by belt 56 connected to a suitable source 01' power not shown. The precipitated wax slurry containing propane settling at the bottom of the wax separator 84 is removed from the separator through line 88 controlled by valve 89 and pump 18 which forces the slurry through-heating coil 1| where its temperature is raised to vaporize residual pro-, pane and is then passed into separator 12. Vaporized propane is passedto propane storage tank 21 via line 13 controlled byvalve 14, compressor 58 and cooler 5|. The propane-free wax is withdrawn from the separator via line 15 controlled by valve 16 and pump 11 into storage tank 18.

The chilled oil dissolved in propane and benzol and freed from wax is withdrawn from the vaportight separator 84 via line 88 by means of pump 8| which forces the mixture through valve 82 into evaporator I33. Heat is supplied for vaporizing the propane by closed steam coil 84. v The vaporized propane passes'through mist extractor 85 into line 86 controlled by valve. 81, cooled incooler88 and is then passed into separator 88 in which any condensed naphtha andlight oil which was vaporized together with the propane in the evaporator 83 is withdrawn via line 90, while the vaporized propane passes into line 9| and then into line 49 to compressor 50, cooler I into propane storage tank 21;

The propane-free oil containing the heavier solvent, i. e. benzol, is removed from evaporator 83 via line 92 controlled by valve 92 and pumped by pump 93' into line 94 and passed through cooler- 95 where the temperature of the mixture is lowered suificiently, i. e. to approximately F. for subsequent extraction with liquid sulphur dioxide. It is preferable to add further quantities of benzol to the oil so as to make the proportions of benzol to oil equal. The additional benzol may be introduced into line 94 by means of line I9 controlled by valve I9. The

cooled oil from cooler 95 passes by means of line 96 into the lower zone of extraction column 91. Liquid sulphur dioxide from storage tank 98 passes into line 99 controlled by valve 99 and pumped by pump I00 into the upper zone of extraction column91. Due to the difference in the specific gravity of the oil introduced into the lower zone of the extraction column and. the liquid sulphur dioxide introduced into the upper zone of the extraction column, these two liquids tend to separate. As the liquid sulphur dioxide passes down through the ascending column of oil, it dissolves certain components present. This solution of oil in the liquid sulphur dioxide is removed by means of line I02 controlled by valve IOI and line I03 and passed into evaporator I04 provided with mist extractor I05 where the sulphur dioxide present is vaporized with the aid of steam introduced through closed coil I06 and is removed by means of line I0I controlled by valve I08. The vaporized sulphur dioxide then passes. via line I09 to compressor- 4 column 97 passes into line H9 controlled by valve I into auxiliary separator I2I where any remaining liquid sulphur dioxide is separated out and passes into line I22 controlled by valve I23 and line I03 into evaporator I04. The clear oil in the auxiliary separator I 2I is removed through line I24 and is passed to evaporator I25 provided with mist extractor I26 where the. sulphur dioxide present is vaporizedwith the aid of steam circulated through closed coil I21. The sulphur dioxide vapor is removed from the evaporator I25 by means of line I28 controlled by valve I29 and sent by means of line I09 to compressor IIO where it is compressed and passes by means of line III to condenser II2 where it is liquefied and thence through line II4 to' the sulphur dioxide storage tank 98. The sulphur dioxide free oil or raflinate containing benzol in evaporator I25 is passed by means of line I30 controlled by valve I3I and is pumped by pump I32 into storage tank I33.

The foregoing discussion relative to the separation of the oil free from wax into an extract and rafiinate' by means of liquid sulphur dioxide has been describedas being efiected in the presence of the benzol which was originally introduced into the oxidized asphalt from storage tank 2|. Inother words, we have purposely retained the dewaxed oil by means of the heat introduced in evaporator 83 and this solvent condensed and collected at the bottom of separator 89. The subsequent extraction of the oil may then be effected in the presence of equal volumes of other solvents,

such as mineral spirits, boiling between 300 and 400 F. and introduced into the oil via line I9;

It will be further observed that the raflinatefor refined oil collecting in storage tank-I33 and the I: extract collected in storage tank II8will contain the heavier solvent. These oils may be steam topped at approximately 350 F. to remove'the solvent prior to blending with the bitumen' will be hereinafter described. However, if desired,

the admixture with the bitumen with-either the rafiinate or extract may be effected in thepresence of the solvent and then the mixture steamtopped to remove the solvent prior to additional oxidation to be described. Y

In order to effect blending with'the bitumen,

the latter is withdrawn from tank 54 by means of line I34 controlled by valve I35 and pumped by pump I36 through heater I3I into lines I38 and I39 where it may be mixed with the rafiinate from tank I33 introduced into line I39 via line I40 controlled by valve MI and pump I42 or with the extract from tank II 8 introduced into the bitumen by means of line I43 controlled by valve I44 and pump I45. Either mixture is then passed via line I46 into an auxiliary oxidizing 1 still I4'I set in furnace I48 and heated by burners I49. Air or other oxidizing gas is introduced into the still via perforated line I50 controlled by valve I5I. Light oils, fixed gases and excess air are removed through mist extractor I52 and pass into line I53, thence through condenser I54, into line I55 and then into run-down tank I56.

Fixed gases and air are vented through I5'I.'

The oxidation is carried on in still I" until the admixture is brought to a proper specification whereupon it is removed from the still via line I 58 controlled by valve I59 and pumped by pump I60 into storage tank I6I.

The above description of the process has beenmade with reference to the blending of the bitumen with either the raflinate or extract produced from the original oxidized asphalt. If desired, and depending upon the amount of oil required in mixture to give a composite asphalt of desired specification as to melting point, penetration and ductility, additional quantities of the same blending oil may be introduced into the bitumen from storage tank I62 withdrawn via line I63 controlled by valve I 64 and pumped by pump I65 into line I39. If desired, the blending oil from either tanks H8 or I33 may be supple- 1 closing valve I 46'- and openingv valve -I66ion line I6'I the blend may be passed to storage tank I68. Asan alternative method for producing a battery sealing compound or roofing-cement, an oil oxidized into asphalt to approximately 200 F.

melting point, a penetration of at 77 F. and a ductility of 2 cm. at 77 F. and of 0 at 32 F. and having a flash point of approximately 430 F. may be distilled by steam distillation to re- 7 of approximately 375 to 425 F. and a viscosity 0! 800 to 2000 seconds Saybolt universal at 100 F. or a high flash point lubricating oil produced from a mid-continent or Eastern crude of paraflln base or petrolatum. The blend oi the bitumen or bottom: and the saturated type oil may then be blown additionally with air and steam to produce a synthesized asphalt having a melting point of 200 F., a penetration of 65 at 77 F., a ductility of 2 cm. and 2 cm. respectively, at 77 F. and 32 F. and a flash point of 500 F. It will be observed that the penetration at 77 F. and the ductility at 32 F. have been increased considerably over the same tests on the original oxidized asphalt and the composite asphalt is more suitable as a battery sealing compound due to these increased properties than the original oxidized asphalt.

The foregoing exemplary description is merely illustrative of preferred modes of carrying out our invention and isnot to be taken as limiting as many variations may be made within the scope of the following claims by a. person skilled in the art without departing from the spirit thereof.

We claim:

1. A process for producing asphalt which comprises oxidizing an oil to produce an oxidized asphalt, separating said oxidized asphalt into an oil fraction and a bitumen fraction substantially free from oil and commingling said bitumen fraction with oil having a flash point between 375 F. and 425 F. and a viscosity of 800 to 2000 seconds Saybolt universal at 100 F.

2. A process for producing asphalt which comprises oxidizing an oil to produce an oxidized asphalt, separating said oxidized asphalt into an oil fraction and a bitumen fraction substantially free from oil and commingling said bitumen fraction with oil having a flash point approximately between 375 F. and 425 F.

.3. A process for producing asphalt which comprises oxidizing an oil to produce an oxidizing asphalt, separating said oxidized asphalt into an oil fraction and a bitumen fraction substantially free from oil and commingling said bitumen fraction with oil of higher gravity viscosity constant than said separated oil.

4. A process for producing asphalt which com-- priseoxidizing an oil to produce an oxidized asphalt, separating said oxidized asphalt into its bitumen and oil constituents by means of solvents and blending said separated bitumen with oil having a higher gravity viscosity constant than the oil originally present in said oxidized asphalt.

5. A process for producing asphalt which comprises oxidizing an oil to produce an oxidized asphalt, separating said oxidized oil into an oil fraction and a bitumen fraction substantially free from oil by mean sot distillation and blending said separated bitumen with oil having a higher gravity viscosity constant than the oil originally present in said oxidized asphalt.

6. A process for producing asphalt which comprises oxidizing an oil to produce an oxidized asphalt, separating said oxidized asphalt into an oil fraction and a bitumen fraction substantially free from oil, blending said separated bitumen with oil having a flash point approximately between 375 F. and 425 F. and oxidizing said mixture.

7. A process for producing asphalt which comprises subjecting an asphaltic residue to oxidation with air to produce arroxidized asphalt, commingling said oxidized asphalt with a solvent capable of dissolving the oil constituent of said oxidized asphalt and to precipitate its bitumen constituent, separating the oil solvent solution from the bitumen, commingling said bitumen with an oil of higher gravity viscosity constant than the oil separated by said solvent and oxidizing said mixture.

8. A process for producing asphalt which comprises subjecting an asphaltic residual oil to oxidation with air to produce an oxidized asphalt, commingling said oxidized oil with a liquefled normally gaseous hydrocarbon solvent under pressure to separate said oxidized asphalt into its oil and bitumen constituents, commingling the oil constituent with a solvent capable of separating said oil into an'oil having a low gravity viscosity constant and an oil having a high gravity viscosity constant, separating said oils from each other and commingling said toil having a high gravity viscosity constant with said bitumen and subjecting said mixture to fm'ther oxidation.

9. A process for producing asphalt which comprises subjecting an asphaltic residual oil to oxidation with air to produce an oxidized asphalt, separating said oxidized asphalt into its oil and bitumen constituents by means of solvents, commingling said oil constituent with liquid sulphur dioxide to separate said oil constituent into.a rafllnate and extract, commingling said extract with said bitumen and subjecting said mixture to further oxidation with air. whereby an asphalt is produced having a lower penetration for the same melting point and a relatively higher susceptibility to temperature change than said first mentioned oxidized asphalt.

10. A process for producing asphalt which com prises subjecting an asphaltic residual oil to oxidation with air to produce an oxidized asphalt, separating said oxidized asphalt into its oil and bitumen constituents by means of liquid propane, separating said oil constituent into an oil having a low gravity viscosity constant and an. oil having a high gravity viscosity constant, commingling said 011 having a high gravity viscosity constant and said bitumen and adding to said mixture oils of higher gravity viscosity constant than the oil constituents separated from said oxidized asphalt.

11. A composite asphalt produced from an oxidized asphalt in which the oil constituent of the oxidized asphalt has been replaced with oil of lower paraflinicity, said synthesized asphalt having a lower penetration at 77 F. for the same melting point and a higher ductility at 77 F. for melting points below 210 F. than said oxidized asphalt.

12. A composite asphalt produced from an oxidized asphalt in which the oil constituent of the oxidized asphalt has been replaced with oil oflower parafilnicity, said synthesized asphalt having a higher ductility at 77 F. for melting points below 210 F. than said oxidized asphalt,

substantially the same penetration at 77 F. and a lower melting point than said oxidized asphalt for the same amount of oil in said asphalt. 13. A composite asphalt produced from an oxidized asphalt in which substantially all of the oil constituent of the oxidized asphalt has been replaced with oil having a flash point between approximately 375 and 425 F. and a viscosity of 800 to 2000 seconds Saybolt universal at 100- F. 14. A composite asphalt produced from an oxidized asphalt in which substantially all of the oil constituent of the oxidized asphalt has been replaced with an oil having a flashpoint between approximately 375 F. and 425 F.

15. A composite asphalt produced from an' oxidized asphalt in which the oil constituent of the oxidized asphalt has been replaced with an oil having a flash point between approximately 375 F. and 425 F. said composite asphalt having a meltingpoint of approximately 200 F., a penetration at 77 F. of approximately 65, a ductility of approximately 2 and 2 cm. respectively at 77 F. and 32 F. and a flash point of approximately 500 F.

ULRIC B. BRAY. LAWTON B. BECKWITH. 

